Implantable medical devices (IMDs) are devices designed to be implanted into a patient. Some examples of these devices include cardiac function management (CFM) devices such as implantable pacemakers, implantable cardioverter defibrillators (ICDs), cardiac resynchronization devices, and devices that include a combination of such capabilities. Other examples include implantable devices with neural stimulation capability. The devices are typically used to treat patients using electrical or other therapy and to aid a physician or caregiver in patient diagnosis through internal monitoring of a patient's condition. Other examples of implantable medical devices include implantable diagnostic devices, implantable insulin pumps, or devices implanted to administer drugs to a patient.
The devices may include one or more electrodes in communication with sense amplifiers to monitor activity (e.g., electrical heart activity) within a patient, and often include one or more sensors to monitor one or more other internal patient parameters. In CFM devices, monitoring heart activity signals allows the IMD to detect abnormalities such as tachyarrhythmia or bradycardia. Providing multiple types of therapy to a patient under different protocols may complicate the diagnostic and therapy delivery functions of IMDs.